The present invention relates to dental instruments and more particularly to a self cleaning dental hand mirror. During use, the reflective surface of the dental hand mirror commonly used by dentists quickly becomes obscured from the dentist's high speed drill sprays, dental material and tooth debris, fog, mist, etc. This impaired reflective surface can lead to reduced workmanship in dental operations unless the mirror is constantly cleaned and/or a surface tension reducer constantly applied. It has therefore been customary for dentists to frequently remove these dental mirrors from the patients mouth to facilitate cleaning of the reflective surface and then to reposition the mirror in its original position, a process which is tedious, time consuming and costly. In addition to the time consuming and costly aspects of the present state of the dental mirror art there also arises a lack of concentration and pin point accuracy when the dentist is continuously interrupted to clean the mirror's surface. A few dentists have overcome this difficulty by eliminating the use of the dental hand mirror altogether. However this is often done by positioning the patient at an uncomfortable angle that will facilitate clear direct vision by the use of a special and more costly dental chair. However, many patients do not easily tolerate these uncomfortable positions. Additionally many dentists will crook or bend their necks and backs in an attempt to obtain direct vision, resulting in discomfort for the dentists.
Numerous attempts have been made to solve the problem of foggy, unclean dental mirrors and as early as 1906 a U.S. Pat. No. 838,648 was issued to Oliver T. Robinson, for a self cleaning dental mirror. Since then self cleaning dental mirrors have been proposed where air pressure is used to clean the reflective surface, or where water is used to wash the reflective surface. Each of these attempts, however, has proven unsatisfactory. Air pressure alone fails to prevent the formation of fog, mist, etc. from obscuring the mirror's surface. Likewise, when used alone, water either produces turbulent water patterns which distort the reflective surface beyond visability when supplied at a sufficiently high pressure to remove the high density debris which falls on the reflective surface during normal dental operations or, when supplied at a sufficiently low pressure so that distortion does not occur, does not wash the reflective surface clean of the high density debris. In order to attempt to overcome the various problems in using either air or water alone, devices have been patented that use water and air as an aspirating means. These devices, however, generally only attract the debris and mist to the reflective surface instead of away from it, and furthermore are susceptible to particles of debris clogging the aspirating vacuum inlets producing an uneven water flow and ripples across the mirror resulting in a distorted surface with unclear visibility.
Various other arrangements, including mechanical wipers, have even been tried without success. The most recent devices proposed use a combination air and water external mix nozzle, similar to a standard mouth wash spray device, to produce a spray across the surface of the mirror. Even though these devices remove most of the debris and mist, the turbulent interference patterns created by the spray makes these devices unacceptable because of poor visibility. Until the present invention, there has not been a practical workable self cleaning dental mirror device available to dentists.